Before 3 years ago, it wouldn't have looked like "any other penny asset" it would have had a similar chart as now because its prior booms and busts 3 years prior to that all had similar degrees of amplitude. Just zoom in on a chart and pretend that it is summer 2017 with no future price history available, just like all the traders at the time had.
Regarding "penny asset" again, in price 3 years ago and 6 years ago Bitcoin would have been hundreds of dollars, which is not like penny assets, and even if comparing "penny stocks" to a digital commodity the marketcap of bitcoin 3 even 6 years ago would be greater than 99.9% of anything in the penny stock markets (bulletin boards, pink sheets), of which - of course - commodities and commodities derivative do not trade on.
You speak in hyperbole for emphasis and that's generally fine, but that only works if you know what you are talking about and it is pretty clear you just conflate concepts over and over again.
Its fine if you personally don't want to or don't have the risk profile to be in this market, yes you are missing a lot of alpha from sitting on the sidelines. No, you don't have any insight to support you sitting on the sidelines. But again, it is a completely valid choice to do so.